relationship between postendodontic pain, tooth diagnostic factors, and apical patency

RDAJ

ATotsatmiTaawino(

KAp

(M

DpS0

id

Clinical Research

J

elationship between Postendodontic Pain, Toothiagnostic Factors, and Apical Patency

na Arias, DDS, Dr. Odont,* Magdalena Azabal, MD, DDS, Dr. Med,†

uan J. Hidalgo, MD, DDS, Dr. Odont,* and José C. de la Macorra, MD, DDS, Dr. Med*

ATgc

ftrccs

ric

dptcp

tdhrc

otdi

opmdt

R

lw

bstracthis study compares the incidence, degree, and lengthf postoperative pain in 300 endodontically treatedeeth, with and without apical patency, in relation toome diagnostic factors (vitality, presence of preoper-tive pain, group, and mandible of treated tooth). Ofhe questionnaires received back, apical patency wasaintained during shaping procedures with a #10 K-file

n one group (n � 115) and not in the other (n � 121).here was significantly less postendodontic pain whenpical patency was maintained in nonvital teeth. If painppeared, its duration was longer when apical patencyas maintained in teeth with previous pain or located

n the mandible. Maintenance of apical patency doesot increase the incidence, degree, or duration of post-perative pain when considering all variables together.J Endod 2009;35:189–192)

ey Wordspical patency, postendodontic pain, postoperativeain

From the *Department of Conservative Dentistry, FacultyEstomatologia II) of Odontology, Complutense University of

adrid, Spain; and †Private practice, Madrid, Spain.Address requests for reprints to José C. de la Macorra,

epartment of Estomatologia II, Faculty of Odontology, Com-lutense University, Plaza Ramon y Cajal s/n, 28040 Madrid,pain. E-mail address: [email protected]/$0 - see front matter

© 2008 Published by Elsevier Inc. on behalf of the Amer-can Association of Endodontists.oi:10.1016/j.joen.2008.11.014

o

OE — Volume 35, Number 2, February 2009

ccumulation of soft tissue remnants or of dentinal debris in the apical region is acommon event that can cause blockage of root canal, normally in its apical third.

his can be avoided if patency of the apical foramen during the shaping procedure isranted (1). Currently, maintaining apical patency is recommended during shaping andleaning endodontic procedures (2, 3).

Apical patency is a technique in which the apical portion of the canal is maintainedree of debris by recapitulation with a small file through the apical foramen (4, 5). Thisechnique allows prevention of blockage (6 –9). The most predictable method is toegularly use a so-called patency file during cleaning and shaping procedures. This filean be defined as a small flexible K-file, which is passively moved through the apicalonstriction without widening it (10). The files used to obtain patency are often theame files initially used to negotiate canals (11).

Other advantages of this procedure are that it minimizes the risk of loss of length,educes canal transportation and other accidents such as ledges (10), eases irrigationn the apical third of the canal (12), allows maintenance of the anatomy of the apicalonstriction (6), and improves the tactile sense of the clinician during apical shaping (10).

One of the alleged reasons for not using apical patency is the possible extrusion ofebris through the apical foramen, a condition classically related with postoperativeain. In fact, the patency concept is controversial to some practitioners (13). Somehink that the repeated pass of patency files, even of small ones, through the apex canause by itself a periapical acute inflammatory response (9) and severe postoperativeain (13).

This procedure is taught in 50% of U. S. dental schools. In the other half, thisechnique is not taught, arguing that apical patency might increase the displacement ofebris and subsequently irritate the periodontal ligament without producing a betterealing (9). However, Tsesis et al. (14) found that maintaining apical patency did noteduce apical transportation or have an effect on loss of working length in curved rootanals.

Other authors stated that maintaining apical patency would not cause more post-perative problems, providing it is satisfactorily made (9), and that its benefits exceed

he possible injury it might cause (6) because it is intended exclusively to prevententinal chips being compacted into the apical region and forming a plug that can

nterfere with maintaining working length (15).We have not found any published research assessing the incidence of postend-

dontic pain when apical patency was maintained in relation to when it was not. Theurpose of this prospective study was to assess whether maintaining apical patencyight influence the incidence, degree, or duration of postoperative pain, considering

ifferent tooth diagnostic factors such as pulpal status, preoperative pain, or the posi-ion or group of the teeth to be treated.

Materials and MethodsThis research was conducted with the approval of the Ethics Committee of Clinical

esearch of Saint Carlos Hospital-Madrid.Three hundred endodontic treatments were performed in uniradicular, biradicu-

ar, and multiradicular teeth by one endodontist, all of them in single visits. All patientsere informed of the aims and design of the study, and written authorizations were
btained before their inclusion.
Relationship between Postendodontic Pain, Tooth Diagnostic Factors, and Apical Patency 189

mailto:[email protected]

uca

seopct(dp

emuYrMowGceAiIfpWIm(fnfdig#w

nmKed

aropms

pg

(ctr

t1

P

g

ssb

Owi

P

g

TP

T(

T(

Clinical Research

1

Exclusion criteria were the need for retreatment, pregnancy, fail-re to obtain patient’s authorization, and the presence of accidents oromplications during treatment (calcified canals, impossibility ofchieving apical patency in any canal).

The following data were collected in clinical records. Pulpal vitalitytatus (vital/nonvital) was assessed through thermic stimulation withthyl chloride spray. This status was rechecked by testing the presencef bleeding during the endodontic access. If the thermic stimulation wasositive and there was bleeding during endodontic access, the tooth wasonsidered as vital and as nonvital if the stimulation was negative orhere was no bleeding. The presence or absence of preoperative painyes/no) was noted. We asked the patients whether they had pain theays before the appointment. Group of teeth (posterior/anterior) andosition (superior/inferior) were also collected.

Patients were given local anesthetics (lidocaine hydrochloride andpinephrine 1:80,000; Xilonibsa, Inibsa, Spain). The standard treat-ent procedure consisted of the following steps. Access was obtained by

sing 014 round carbide and Endo Z burs (Dentsply International,ork, PA), with high-speed and water refrigeration at all moments. Fullubber dam was placed in the tooth to be treated. GLYDE (Dentsplyaillefer, Ballaigues, Switzerland) lubricant was placed at the entrance

f the canals. Negotiation was done with a #10 file. Determination oforking length was made with Root ZX apex locator (J Morita EuropeVBH, Frankfurt, Germany), with radiographic confirmation. Pulpalhamber was blot-dried with a cotton pellet. Lubricant was placed at thentrance of canals (ie, measurements were made along moist canals).#10 file clamped to Root ZX apex locator was used to measure work-

ng length. Repetition of measurement was made with #12 and #15 files.f there was no agreement between measures obtained by using the 3iles, the measure that was dissimilar was reassessed. If disagreementersisted, the measure delivered with the thicker file was selected.orking length was confirmed with an intraoral periapical radiograph.

n case of disagreement between radiographic and electronic measure-ents, the latter was selected. Shaping was done with Gates-Glidden

Dentsply Maillefer) and K-flexofile (Dentsply Maillefer). Master apicaliles ranged from #20 –#30 in narrow and from #25–#40 in wide ca-als. After shaping of coronal and mid thirds, working length was con-irmed by using apex locator. Cleaning with 5% NaOCl was performeduring all procedures. AH-Plus sealer (Dentsply Maillefer) was depos-ted in canal by using an impregnated master cone twice. The #15utta-percha cones (Dentsply Maillefer) were laterally condensed with20 nickel-titanium spreaders (Dentsply Maillefer) 1 mm short oforking length.

Patients were randomly assigned to 1 of 2 groups: patency (P) ando patency (NP). In group P (initial n � 150), apical patency wasaintained throughout shaping and cleaning procedures by using a #10

-file between each instrument. In group NP (initial n � 150), allfforts were made to avoid surpassing the working length at all timesuring treatment.

ABLE 1. Chi-Square Test Results in Analysis of Incidence of Postoperativeain (outcomes: yes/no)

Diagnostic factor Condition n P value

Previous status Vital 145 .47Nonvital 91 .03

Preoperative pain Yes 76 .29No 160 .054

Group Posterior 152 .07Anterior 84 .59

Position Upper 121 .64
Lower 115 .08
90 Arias et al.

Patients were informed of the possible occurrence of pain for daysfter treatment and were given a questionnaire to be completed andeturned. In it, they would record the presence or absence of postend-dontic pain, its duration and level of discomfort rated as follows: mildain: any discomfort of any duration that does not require treatment;oderate pain: pain that requires and is relieved with analgesics; and

evere pain: any pain that is not relieved with treatment (analgesics).Two hundred thirty-six of the 300 questionnaires were returned

roperly answered. Of these, 121 belonged to P group and 115 to NProup.

Results of groups P and NP related to incidence (yes/no), degreemild, moderate, severe), and length (days) of postoperative pain wereompared, attending to diagnostic factors: status of tooth (vital/nonvi-al), presence or absence of preoperative pain, group of teeth (poste-ior or anterior), or position (superior, inferior).

Results were analyzed with the �2 test for the incidence of pain, therend test for its degree, and Mann-Whitney U test for its duration (SPSS5 for Windows; SPSS Inc, Chicago, IL).

ResultsResults are shown in Tables 1, 2, and 3.

revious Vital StatusDifferences were not statistically significant between P and NP

roups regarding degree or duration of pain.Incidence of postoperative pain differences was not statistically

ignificant except in the group of nonvital teeth, where incidence wasignificantly lower (P � .03) when apical patency was maintained (Ta-le 1).

Odds ratio was 2.53 (95% confidence interval [CI], 1.03–3.70).dds of postendodontic pain in nonvital teeth in which apical patencyas not maintained (NP) were between 1.03 and 3.70 times higher than

n P group, in which patency was maintained.

resence of Preoperative PainDifferences were not statistically significant between P and NP

roups regarding incidence or degree of postoperative pain.

ABLE 2. Trend Test Results in Analysis of Degree of Postoperative Painoutcomes: mild/moderate/severe)





Position Upper 63 .82Lower 59 .16

ABLE 3. Mann-Whitney U Test in Analysis of Duration of Postoperative Painoutcome: days)





Position Upper 63 .09
Lower 59 .016
JOE — Volume 35, Number 2, February 2009

e3pm

G

gw

P

so

.wp

tqb

bgbtw

ecapa

cas

poMtvtacaeofr

eihwot

tdpctwpmwawhw

oinelpt

edadofpdbi

ittirtl

pmr

l(

bp

Clinical Research

J

In cases with reported presence of preoperative pain, days of pres-nce of postendodontic pain were significantly more (P � .006; Table) when apical patency was maintained. With a 95% CI, postoperativeain was between 0.47 and 3.19 days longer if apical patency wasaintained, in patients who had experienced pain before treatment.

roup of TeethThere were no statistically significant differences between P and NP

roups regarding incidence, degree, or duration of postoperative painhen anterior teeth were compared with posterior.

ostendodontic Pain Related to the ArchIn upper teeth, differences between P and NP groups were not

tatistically significant regarding incidence, degree, or duration of post-perative pain.

In lower teeth, postoperative pain was significantly longer (P �016; Table 3) if apical patency was maintained. In this group of teethith a 95% CI, pain was between 0.08 and 2.63 days longer if apicalatency was maintained.

DiscussionOne of the main problems in studying pain is the patient’s subjec-

ive evaluation and its measurement. For this reason, design of theuestionnaire is critical and must ensure that it will be fully understoody patients and easily interpreted by researchers.

In this report, a simple verbal categorization was used in the feed-ack form with 3 categories: mild, moderate, and severe. These cate-ories were straightforwardly understood by patients and were definedy the presence or absence of the need for analgesic treatment and byhe relief it produced. However, subjectivity remained in the decision ofhether to have analgesic treatment.

In this study, accurate determination of working length was alsossential. It was determined with an electronic apex locator and lateronfirmed with a radiograph. Root ZX locator was used because itsccuracy has been confirmed in vitro (16) and in vivo (17–19). Asroposed by Herrera et al. (20), electronic measurement was repeatedfter mid and coronal shaping.

When radiologic and electronic root canal measurements areombined, sometimes results do not coincide. In the event of discrep-ncy between both measurements, the electronically determined valuehould be preferred (21–23), as in this study.

Another central factor is the definition of the file to be used in theatency protocol. There is not an explicit description other than the #10r #15 file used to negotiate canals (24). In the report by Cailleteau andullaney (9) on teaching of patency in U.S. dental schools, the size of

he instrument used to maintain the opening in the apical foramenaried. The #10 file was used by 42%, 33% used #15 file, and 25% usedhe #20 file. We systematically used a #10 diameter file to maintainpical patency in this study. Using high diameters for this purpose canause injury of periapical tissues, difficult control in filling technique,nd extrusion of important amounts of infected debris; all of theseffects increase the incidence of postendodontic pain and put the resultf the treatment at risk. Goldberg and Masson (8) observed that if a #20ile is used as a patency file, the chance of transporting apical forameneaches 56.6%.

Forcing of endodontic instruments beyond the apical foramen canxtrude a variety of irritants to the periapical tissue, which can increasencidence and degree of pain (25). One study showed a significantlyigher incidence of pain if during the shaping procedure, instrumentsere forced beyond the apical foramen instead of maintaining them 1.5r 2 mm short from the radiographic apex (26). Although it is difficult
o compare their results with ours because there is no overinstrumen-
OE — Volume 35, Number 2, February 2009 Relationship

ation in our protocol but a patency preservation in some cases, our dataiffer in that in nonvital teeth, patency cases show less postoperativeain when compared with nonpatency cases (P � .03), probably be-ause debris or microorganisms in the apex irritate more periapicalissue than a small file that passively moves through apical foramen,hich is wider than the 0.12 mm of diameter at d1 of a #10 file, theatency file used in our research. In our study, apical patency wasaintained with a 10 file passively moved 1 mm beyond working length,hereas in the cited report it is unclear how much farther from thepical foramen the instruments were forced, or which diameters of filesere used. In addition, in our report all cases were treated by the sameighly experienced endodontist, whereas in the other report patientsere treated by undergraduate students.

However, apical patency does not seem to be related to postend-dontic pain in vital teeth. It is in this group of teeth in which agreement

s lower between clinicians; one possible explanation is that this tech-ique is not as damaging to periapical tissues as its critics believe. Foxt al. (27) did not find statistically significant differences in the estab-ishment of postoperative pain with controlled overinstrumentations, aositively more aggressive technique than just maintaining apical pa-

ency.Moreover, Torabinejad et al. (28) found that unintentional over-

xtension of files, which can happen while determining working length,oes not affect the incidence of postoperative pain. Probably they usedmethodology similar to ours, because likely they used only fine files toetermine the working length. This supports the idea that these are thenly files that should invade the periapex. This report supports our

indings in that periapical overextension does not necessarily causeostoperative pain. However, it differs from our study in that the authorsid not try to maintain apical patency during all the shaping procedure,ut overextension of files through apical foramen was limited to work-

ng length determination.In a different type of research, Siqueira et al. (29) found low

ncidence of flare-ups after shaping and cleaning 627 nonvital teeth oreeth with previous endodontic treatment if apical patency was main-ained. They stated that maintenance of apical patency does not seem tonfluence postoperative pain. This was not assessed in our study. In oureport, flare-ups were not evaluated, only postoperative pain, and pa-ency #10 files were not forced farther than 1 mm beyond workingength, including necrotic teeth with periapical radiolucencies.

In conclusion, when vitality of teeth is considered, the incidence ofostendodontic pain is lower in nonvital teeth when apical patency isaintained, with an odds ratio of 3.1 (95% CI, 1.1– 8.8), and the du-

ation is longer in lower teeth (95% CI, 0.08 –2.6 days).When preclinical symptoms are considered, duration of pain is

onger in teeth with previous pain when apical patency is maintained95% CI, 0.5–3.2 days).

From our data, it can be concluded that maintaining apical patencyy using a #10 K-file can compensate for the eventual longer duration ofostoperative pain in certain cases.

References1. Soares I, Goldberg F. Endodoncia: técnica y fundamentos. Editorial Médica Pana-

mericana 2002:105.2. Monsef M, Hamedzadeh K, Soluti A. Effect of apical patency on the apical seal of

obturated canals. J Endod 1997;23:253.3. Monsef M, Hamedzadeh K, Soluti A. Effect of apical patency on the apical seal of

obturated canals. J Endod 1998;24:284.4. Schilder H. Canal debridement and disinfection. In: Pathways of the pulp. St Louis:

C. V. Mosby Co, 1976:119.5. Glossary of endodontics terms. 7th ed. Chicago, IL: American Association of End-

odontists;2003.

between Postendodontic Pain, Tooth Diagnostic Factors, and Apical Patency 191

1

1

1

1

1

1

1

1

1

1

2

2

2

2

2

2

2

2

2

2

Clinical Research

1

6. Canalda C, Brau E. Endodoncia: técnicas clínicas y bases científicas. Milan, Italy:Masson, 2001.

7. Fava L. Acute apical periodontitis: incidence of post-operative pain using two differ-ent root canal dressings. Int End J 1998;31:343–7.

8. Goldberg F, Masson E. Patency file and apical transportation: an in vitro study. JEndod 2002;28:510 –1.

9. Caillateau J, Mullaney T. Prevalence of teaching apical patency and various instru-mentation and obturation techniques in United States dental schools. J Endod1997;23:394 – 6.

0. Buchanan LS. Management of the curved root canal. J Calif Dent Assoc1989;17:18 –27.

1. Izu KH, Thomas SJ, Zhang P, Izu AE, Michalek S. Effectiveness of sodium hypochloritein preventing inoculation of periapical tissues with contaminated patency files. JEndod 2004;30:92– 4.

2. Flanders D. Endodontic patency: how to get it, how to keep it, why it is so important.N J State Dent J 2002;68:30 –2.

3. Buchanan LS. Cleaning and shaping of the root canal system. In: Cohen S, Burns RC,eds. Pathways of the pulp. 5th ed. St Louis, MO: Mosby, 1991.

4. Tsesis I, Amdor B, Tamse A, Kfir A. The effect of maintaining apical patency on canaltransportation. Int Endod J 2008;41:431–5.

5. Souza R. The importance of apical patency and cleaning of the apical foramen on rootcanal preparation. Braz Dent J 2006;17:6 –9.

6. Luiz F, Santana D, Correia L. The ability of two apex locators to locate the apicalforamen: an in vitro study. J Endod 2006;32:560 –2.

7. Tselnik M, Baumgartner J, Gordon Marshall J. An evaluation of Root ZX and Elementsdiagnostic apex locators. J Endod 2006;31:507–9.

8. Welk A, Baumgartner J, Gordon Marshall J. An in vivo comparison of two frequency-
based electronic apex locators. J Endod 2003;29:497–500.
92 Arias et al.

9. Dunlap CA, Remeikis NA, BeGole EA, Rauschenberger CR. An in vivo evaluation of anelectronic apex locator that uses the ratio method in vital and necrotic canals. JEndod 1998;24:48 –50.

0. Herrera MC, Abalos A, Planas J, Llamas R. Influence of apical constriction diameteron Root ZX apex locator precision. J Endod 2007;33:995– 8.

1. Lucena-Martín C, Robles-Gijón V, Ferrer-Luque CM, Navajas-Rodriguez de MondeloJM. In vitro evaluation of the accuracy of three electronic apex locators. J Endod2004;30:231–3.

2. Kim-Park MA, Baughan LW, Hatwell GR. Working length determination in palatalroots of maxillary molars. J Endod 2003;29:58 – 61.

3. Williams CB, Joyce AP, Roberts S. A comparison between in vivo radiographic work-ing length determination and measurement after extraction. J Endod 2006;32:624 –7.

4. Peters O, Peters C. Limpieza y conformación del sistema de conductos radiculares.In: Cohen S, Burns RC, eds. Vías de la pulpa (Español). 9th ed. New York: Elsevier,2008.

5. Nobuhara W, Carnes D, Gilles J. Anti-inflammatory effects of dexamethasone onperiapical tissues following endodontic overinstrumentation. J Endod 1993;19:501–7.

6. Georgepoulou M, Anastassiadis P, Sykaras S. Pain after chemomechanical prepara-tion. Int End J 1986;19:309 –14.

7. Fox J, Atkinson J, Dinin A, et al. Incidente of pain following one-visit endodontictreatment. Oral Surg 1970;30:123–30.

8. Torabinejad M, Kettering J, McGraw J, Cummings R, Dwyer T, Tobias T. Factorsassociated with endodontic interappointment emergencies of teeth with necroticpulps. J Endod 1988;14:261– 6.

9. Siqueira J, Rôças I, Favieri A, et al. Incidence of postoperative pain after intracanal
procedures based on an antimicrobial strategy. J Endod 2002;28:457– 60.
JOE — Volume 35, Number 2, February 2009

relationship between postendodontic pain, tooth diagnostic factors, and apical patency

Documents